Biaxial shoe



Aug' l1, 1953 H. c. STEIN 2,648,144 BIAXIAL SHOE Filed Sept. 19, 1951v TIBIA AXIS OF WEIGHT-w Il i f` Axis oF a, BEARING-b INVENTOI M Amsy/ Patented ug. 11., 195.3

UNITE-Df- OFFICE i SHOE Harry Gnarles stein, Yonkers', N. Y., assigner of one-fifth `to Leonard J. Stein, Hous'ton, Tex., one-fthfto Stanley M. Stein, Nevgrleans, La., onel-fifth-f toik Melvin Stein; l J aeksyon Heights; N. Y.; and one-Ifth to FrankiR; Stein; Yonkers,`I N.

AlmleatiinY september 19, 1951;' serfl' N; ,247,245Y s claims., (crisi- 815) vMy invention relates toshoes'and shoe, lasts.

and more particularly to shoes which are -physif` ological in character. Itis expected, thereby-,to establish a closer equilibrium between the foot and its clothing than exists between the footand its'present type of covering; i M While the problem of equilibriumAv hasbeenrecognizedv since 1819, when right andleft shoes rst made their appearance, little ha`sbeen done thereafter for the preservation ofgfootfunction. Shoes have been corrective,4 ratherthan correct, and eiorts havebeen largelyconi'ined to orthopedic shoes dealing' with abnormalities ofthefoot. l As an example of improper equilibrium, the. conventional shoe last for makingA4 shoes forf'the,

normal foot is built on avertical axis passing centrally through the tibia. However, the ver-v tical axis or the axis of weightbearing isthrough'V the calcaneus and is located from:one" to two centimeters lateral to that oi the tibia.

Accordingly, the principal object of in-vv vention is to provide a shoe last wherein the Vertical axis of the heel coincides with theax'ivs; through the calcaneus, rather than throughthe tibia.

The conventional shoe last has a horizontal axis extending from its intersection withthe vertical axis through the tibia to theregionof' the third metatarsal head. Thisrposition ofthe axis is intended. to produce'vv symmetry` in the shoe.

which are the static or standing a'xis,',an'dfvtli'er dynamic axis, the axis of locomotion. l,Unlesslthe calcaneus is centered' to the heel' ofV the shoe, there cannot be mechanical equilibrium beltween the foot and the shoe in either axis.` yIt' is, therefore, a further object .to provide correct' static and dynamic axes for the shoe' and'lasti which more nearly correspond to the bio-lmechanic demands of the foot.

The dynamic axis I have determinedext'endsf medially oblique from the laterally positioned" calcaneus, to the medially positionedlball ofjrthe big toe.

dynamic axis.

Further objects include the re-location of the,v peaks of the longitudinal arches inediallydand laterally; the corresponding shift intheantfrioljk transverse metatarsal arch region; and the;other changes made necessary-to insure;y l thef-fvsmooth vforward transfer of the forces of locomotion The axis of symmetry is infactv diier-V ent from the two principal axesY ofthe foot,

Accordingly another object of rn'y'in',` vention comprises the realignment offthe axis. of the conventional heel and toe sections to them, bones of the right footindicating t he eccentric-f.

ityexisting;,between the axis ofweight andthe azdsoibearine..

,Fia ,21s aplan view ora .conventional military.. right `slice-last arbitrarily dividedA into toe, body.

. and heelsections;

Eig. 3 asimilarlviiv.; illustrating a latral. shirn in them heeljection. made pursuant; t0` my.. teachings, the original position being shown inr the.;.dotdash lines.;A 4 Fig.4, illustrates the, ,sarne view, -the position 0fy the. original.. last; beine; shown in dot-dash..-

lines, .With angulationimposed on theheeleftion .to .plage itin thedynamic. axis. the` toe .section repositioned; accordingly, and` all refashioned; intoanew last.

l Eig.; 5;- isla.longitudinallysectioned view ofthe right shoeandlastviewed medially.

Eig,` 6 isapartal sectioned Viewy thereof,

`along the plane 6--6A and in an anterior direc- ,Figv isfa'parnarviw taken in theylcmitywof.

the; s ca'phoid,bone, namelyv in the plane '1 -'1.- n Figi. 8 is a similar View taken in the plane 8 8.

Fig. Elisatransversfe v secftional ViewA of a shoe'A iinwhicsh the heel is provided with a lateral ex?.

tension. i Y N Fig.,Y 10is a partial sideelevation of a shoecmployingwamodifie'd form of a, shank wedge.

Fig, llis aplan View. ofthe same.

l Ingrllig., Y1 ofthe drawings; I have diag.ramfr'iaticallyrshown in aposterior View, the bones,l of the."v

rightA` root,il lustrating ther lateral eceentricityA existing; between thewaxis of bearing through thecalcaneus, andthe` axis of weightA positioned` centrallydhrough the tibia. Depending on the age of the individualf andlother factors', this ,'ecff centricityvvaries. Ifrom, approximately one to two centimeters, andis indicated as e.

In Fig. 2,',th`e'rfe'` is'indicated a plan view,.of a", rightdcbufvenuo-na1 military shoe last m. di; agrammatically divided for convenience into bedr, heel, andgtoe.- ,Sections l I'. I2V and i ,f I rf SiiilirelyA The umich# axis 0f Weight through thervjubiauisincicateu by w andthe axisof bearfl ing through the calcaneus, actually/the medialr 3 calcaneal tubercle, is indicated by b. The horizontal axis, or the axis of symmetry for the conventional shoe last, is s, passing through the axis of weight and the region of the third metatarsal head.

I overcome the instability of the conventional shoe and last brought about by the failure to recognize the aforementioned lateral eccenttricity of the calcaneus with respect to the ankle bone, by a number of changes starting with a lateral shift of from one to two centimeters in the heel section. This is indicated diagrammatically by the new heel position shown in solid lines, or I2c in Fig. 3.

Since the calcaneus, or heel bone, dominates the action of the entire foot, and must be equilibriated with the shoe to insure maximum function, Ihave, by my compensation, co-axially centered and aligned the calcaneus with the heel of the shoe. A shoe with a heel so positioned, enables the calcaneus to correctly receive and evenly redistribute the load of the body weight.

The calcaneus forms the posterior pier of both the medial and lateral longitudinal arches which serve to direct the streams of force toward the great toe when the individual is walking, or along the dynamically loaded axis L. Accordingly, I propose to angulate the transposed section of the heel into its new position I2d to face squarely the ball of the great toe.

In order to establish the dynamically loaded axis, full provision must be made for unimpaired function of the great toe in its nal discharge of force from the ground, referred to as the toe snap. The forepart of the shoe last or toe section I3 is therefore reconstructed in the dynamically loaded axis or in the position indicated as I3d.

There is thus provided ample space for unimpaired great toe function without any deflection, an important factor since the slightest deiiection along the course of the great toe greatly impairs the complete fulfillment of its function.

The original body section II, which becomes the central portion of the last, is contoured to smoothly merge with the re-constituted toe and heel sections by filling it at points f and g and cutting away at points h and 7' to complete the outline of the final shoe last IOcl.

The establishment of the dynamically loaded axis L requires a re-alignment of the longitudinal arches. As shown in Fig. 5, I establish the longitudinal arch I4 in the shoe last with its peak I4d located approximately at the level of the ligamentous junction of the calcaneus with the scaphoid bone on the medial side and at the level I5d of the junction with the cuboid bone on the lateral side as shown in Fig. 6. The peak is considerably lower and positioned posteriorly of the peak I4a in the present type of shoe shown in dot-dash lines in Fig. 5. It is higher toward the medial side as shown in Fig. 6, and somewhat more distally located on the lateral side.

The posterior pillar Id of the longitudinal arch I4 extends from the peak I4d posteriorly to the region of the inferior medial calcaneal tubercle shown at about I'Id as a short slope, rounded, as at I8d, as it passes under the region of the medial tubercle which forms its pier, as indicated in Fig. 5. The sloping of the pillar ISd is somewhat lower and longer on the lateral side.

The anterior pillar I9d of the longitudinal arch portion extends in a longer and more gradual slope from the peaks I4d and I5d to the head 4 of the first metatarsal bone on the medial side and the head of the fifth metatarsal bone on the lateral side. The lateral side is somewhat shorter.

An important aspect of the longitudinal arch is the provision in the medial margin of the shoe 20 of the compartment 20d and between the innersole 20e and the sides 20 f, for the downward projection of the tubercle of the scaphoid bone. The scaphoid is the key bone through which is distributed the stream of forces that go through the medial longitudinal arch, and the present invention accommodates the scaphoid and frees it from the disturbances present in the conventional shoe.

A further change in the construction of the conventional last and shoe, comprises the reversal of the trough or hammock like arrangement in the toe section of the shoe caused by curving the lateral margins upward along the edges, as indicated by the dot-dash lines I3a of Fig. 8. Such trough causes a side rocker effect and results in a central concentration of force of the metatarsal heads, and in the failure to obtain a proper progressive distribution of weight towards the great toe.

In my last and shoe, the lateral margins 20g of the sole portion lie flat, and the base 20h thereof, is slightly elevated under the middle metatarsal head region.

Specific improvements are provided in the external shoe, such as the shank wedge, the sole wedge, and the lateral extension of the heel.

The shank wedge 22 is shown in Fig. 5 in section in Fig. 7, in elevation in Fig. 5, and its plan View position indicated in Fig. 4 by the dotted lines. This wedge, providing a counter-balancing support for the foot, is positioned externally along the lateral half of the outer sole 203i, substantially lateral to the dynamic axis to facilitate the rapid transition from the static to the dynamic loading. The static axis extends from the axis of bearing through the calcaneus to the region of the third metatarsal head. The wedge extends short of the adjacent margin of the anterior outer heel I2lc to preserve the exibility of the shank at this point. This same effect may be obtained by means of a steel spring 23, incorporated in the sole of the shoe in the same location as the wedge and supported at its proximal end on an external underlying solid pier 24, as is illustrated in Figs. 10 and 11, or by the pier itself, if the innersole or shank of the shoe is suiciently resilient.

The sole wedge 25 is provided at the lateral margin behind the bases of the outer toes to act as a counter-support and a guide for the transfer of the forces involved in locomotion along the dynamically loaded axis, even when on toes. Its position is shown in dotted lines in Fig. 4, and in elevation in Fig. 5.

The eccentricity e between the upright axis of weight and the axis of bearing through the calcaneus may be partially accommodated in a modification of the present conventional shoe by an unyielding lateral extension I2L in the outer heel, as shown in Fig. 9. This extension will establish co-axial centering of the calcaneus in the conventional shoe or secure if so desired, a therapeutic over-correction of the co-axially centering involved in the fully correct shoe previously described. Such heel may be entirely moved laterally as indicated by the dot-dash lines I2g, or angulated after lateral movement in the amount e as shown in Fig. 4.

One or more of the above described features of my invention may be applied to innersoles, separate arches, slippers, tennis shoes, sandals, rubbers, bath shoes, shoe trees, and various types of footwear.

In the foregoing invention I have established the relationship between the shoe and the kinetics of the foot as viewed from an engineering point of View. The problem of equilibrium between the shoe and the foot, springs from faulty alignment. In my correct or physiological shoe, as I have termed it, I have established new axes in the shoe for both static and dynamic loads. I have reestablished the congruity of the arches of the shoe with the skeletal arches. I have eliminated the rocker bottom involving the transverse axis of the sole, and have established a proper balance and counterbalance in the transverse plane. I have also provided auxiliary supports, and a stabilizing mechanism to guide unhindered the forward progression of the forces of gait along the dynamically loaded axis. In so doing, I have avoided undue strain of the foot, with its resulting breakdown and faulty and unnatural wear of the shoe.

I have thus described my invention, but I desire it understood that it is n-ot confined to the particular forms or uses shown and decribed, the same being merely illustrative, and that the invention may be carried out in other ways without departing from the spirit of my invention, and, therefore, I claim broadly the right to employ all equivalent instrumentalities coming within the scope of the appended claims, and by means of which, objects of my invention are attained and new results accomplished, as it is obvious that the particular embodiments herein shown and described are only some of the many that can be employed to attain these objects and accomplish these results.

What I claim and desire to secure by Letters Patent, is as follows:

1. A shoe comprising a central portion having a longitudinal axis extending from the region of the center of the ankle through the third metatarsal head region, and a level heel for supporting the foot in an upright position having an unyielding laterally extending projection extending from the front lateral end of the heel to approximately the middle of the rear end of the heel, said projection at approximately the middle exterior side being equal in distance to the eccentricity of the calcaneal tubercle.

2. A shoe comprising a central portion having a longitudinal axis extending from the region of the center of the ankle through the third metatarsal head region, and a counter portion having an oblique axis extending from the region of the medial calcaneal tubercle towards the region of the head of the rst metatarsal bone, said oblique axis offset at the region of the medial calcaneal tubercle to pass through the calcaneal tubercle.

3. A shoe comprising a central portion having a longitudinal axis extending from the region of the center of the ankle through the third metatarsal head region, and a toe portion having an oblique axis extending parallel to a line extending from the medial calcaneal tubercle to the head of the first metatarsal bone, said oblique axis offset suiciently from the longitudinal axis of the central portion at the region of the medial calcaneal tubercle to pass through the calcaneal tubercle.

4. A shoe comprising a central porti-on having a longitudinal axis extending from the region of the center of the ankle through the third metatarsal head region, said central portion having a longitudinal arch portion forming a peak located posterior to the scaphoid tubercle and approximately at the level of the ligamentous junction of the calcaneus with the scaphoid bone on the medial side and at the junction of the calcaneus with the cuboid bone on the lateral side.

5. The shoe of claim 4 provided with a counter portion having a posterior pillar which extends from the peak posteriorly to the region of the nferior medial calcaneal tubercle as a short slope, and is rounded as it passes under the tubercle.

6. The shoe oi claim 4 having an anterior pillar which extends in a gradual slope from the peak forward to and under the head of the first meta tarsal bone on the medial side and to the .head of the lifth metatarsal bone on the lateral side.

7. A shoe comprising a central portion having a longitudinal axis extending from the region of the center of the ankle through the third metatarsal head region, a toe portion and an innersole, said shoe provided with a longitudinal arch portion forming a peak located approximately at the level of the ligamentous junction of the calcaneus with the scaphoid bone on the medial side and at the level of the junction of the calcaneus with the cuboid bone on the lateral side, and having an anterior pillar which extends in a gradual slope from the peak forward to the region of the head of the lirst metatarsal bone on the medial side` and the region of the head of the fifth metatarsal bone on the lateral side, the longitudinal arch portion of the shoe, on the inner sole thereof having a recess in the medial marginal area beneath the region of the scaphoid bone to accommodate the downward projecting tubercle thereof.

8. A shoe comprising a central portion having a longitudinal axis extending from the region of the center of the ankle through the third metatarsal head region, and a counter portion having its longitudinal axis laterally displaced from the longitudinal axis of the central portion by a distance equal to the eccentricity of the calcaneal tubercle, said counter portion joined to said central portion with the medial side pared, and the lateral side filled at the junction margins to provide a smooth merger of the two portions.

HARRY CHARLES STEIN.

References Cited in the le of this patent UNITED STATES PATENTS Number Name Date 29,225 Plumer July 17, 1860 32,487 Plumer June 4, 1861 1,588,911 Ruprich et al June 15, 1926 1,952,684 Sahel et al. Mar. 27, 1934 1,952,685 Sabel et al Mar. 27, 1934 2,078,626 Bauer Apr. 27, 1937 2,088,263 Grouven July 27, 1937 2,210,332 Eich Aug. 6, 1940 FOREIGN PATENTS Number Country Date 629.578 Germany May 6, 1936 

